Multi-Channel Audio Enhancement for Television

ABSTRACT

A comprehensive mechanism is provided for broadcasting and accessing multiple audio sources in connection with the viewing of a television program. In the preferred embodiment, the first step in providing audio is collecting the audio through the use of standard audio capture techniques. Next, the audio is distributed by either of in-band via broadcast or out-of-band techniques. In-band audio is preferably provided via an MPEG stream associated with the current television program. Out-of-band (OOB) audio can be broadcast as well, although it is preferable to select which channel is distributed upstream first, rather than broadcast all channels downstream and consume bandwidth for unselected audio. Thus, it is preferred that only the desired audio channel(s) are sent over the OOB channel. The audio is preferably tagged with metadata, such that information describing the audio accompanies each audio channel. This allows, for example, a description of the audio to be provided to the viewer as part of a selection mechanism (see below), and/or provides control information that is used by the system, for example to configure the system for a particular type of audio processing, e.g. DTS; display accompanying graphic information; such as an ad; or engage a viewer authentication/billing mechanism, for example to provide upstream information concerning the viewer&#39;s selections. With either system, the viewer operates a set top box to select the appropriate audio channel(s) and route the television audio to a television or to a separate amplifier and speakers for reproduction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/242,298, entitled “Multi-Channel AudioEnhancement for Television”, filed Sep. 23, 2011, which is acontinuation application of U.S. patent application Ser. No. 10/103,486,entitled “Multi-Channel Audio Enhancement for Television”, filed Mar.20, 2002, which issued on Oct. 25, 2011 as U.S. Pat. No. 8,046,792, theentire disclosures of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Technical Field

The invention relates to television. More particularly, the inventionrelates to a multi-channel audio enhancement for television.

Description of the Prior Art

Television is currently limited to one channel of audio, with theability to select an alternate audio program, usually in a differentlanguage. During some programs, especially sporting events, there aresituations where the viewer would like to monitor other audio sources.For example, the televising of sporting events offers the opportunity toallow viewers to get in close to the action. Much in the way thatmulti-angle viewing allows viewers to see particular aspects of theevent, the ability to provide multi-source audio would allow viewers tolisten to particularly interesting parts of the program.

For example, the following sporting and other events could be providedto viewers with selectable television audio: NASCAR®. NASCAR fans havetaken up the practice of bringing scanners to races so they can listento the communications between drivers and the pits. This is extremelypopular and could be extended to the home experience. That is, viewerscould listen to the radio channel of their choice through theirtelevision.

Football. There is lots of talking (and grunting) on the field. Thereare also communications from the coaches, e.g. to players and to thebooth. Broadcasters often have mikes on players/coaches and also useparabolic mikes to capture on-field sounds.

Baseball. There is lots of discussion in the dugout. During some gamesin 2001, certain players or coaches were “miked” and held discussionswith announcers in the booth.

Soccer. As with football, coaches can be “miked” and the field can bemonitored.

Golf A selectable audio feature would allow viewers to listen todiscussions between the golfer and the caddy.

Music/Concerts. It may be desirable to hear a particular part of theorchestra or band, separate from the fully mixed music, or to listen tothe stage directions given to the support crew.

News Event. It may be desirable to listen to a commentator rather thanthe speaker, or vice versa.

Track and Field/Olympics. A selectable audio feature would allow viewersto listen to coaches and players.

All Sports. A selectable audio feature would allow viewers to choosewhich announcer to listen to, e.g. in team sports, typically, each teamhas an announcer; or to hear the ambient sounds associated with thesport, thereby heightening the realism of the event for the viewer.

As discussed above, broadcast television presently allows a viewer toselect between a limited number of audio channels. Thus, MTS audioprovides an analog means to provide multiple audio tracks, includingstereo and a second audio program (SAP); and various digital techniques,such as those defined with MPEG, allow additional audio streams to beassociated with a given video stream. Traditional methods involveselecting one of these audio channels during setup.

The British Broadcasting Corporation (BBC) in the UK has demonstratedthe use of more than one audio channel. In this demonstration, the BBCrecorded additional audio, specifically an alternate announcer channeland a “crowd noise” channel. This information was delivered with thevideo in an MPEG stream. An application was created specifically forthis use where the user could press buttons on the remote that weremapped to the audio. When the button was pressed, the audio channel isswitched.

In the BBC demonstration, the entire process is hard coded. That is,there is no descriptive data that accompanies the audio to allow it tobe processed at the receiver. The receiver must have a priori knowledgeof exactly how the audio is sent and what the audio is. For example, thereceiver has no means to determine which channel is crowd noise andwhich one is the announcer. This approach cannot be scaled to anarbitrary number of channels because it depends on buttons. It cannotprovide any information to the user about the channel, either forinformational purposes or to aid in selection. Furthermore, a generalapplication that handles audio under different circumstances cannot bebuilt. Preference engines cannot be implemented to assist the user inselecting suitable or interesting audio channels.

To make a networking analogy, the BBC demonstration represents thelow-level point-to-point protocols, such as PPP, that deliver dataacross a single link. It would be advantageous to address the otherlayers of communication protocol that allow data to be delivered acrossmultiple nodes reliably and to be processed in some useful context atthe end.

It would be advantageous to provide a comprehensive mechanism forbroadcasting and accessing multiple audio sources in connection with theviewing of a television or other program.

SUMMARY OF THE INVENTION

The invention provides a comprehensive mechanism for broadcasting andaccessing multiple audio sources in connection with the viewing of atelevision or other program. One advantage of the invention describedherein is the end-to-end nature and flexibility and generality of thesolution. The invention provides an approach that offers unlimitednumbers of channels. Data can be added to these channels to increase theinterest value and utility of the audio. Once this is done, the combinedaudio and data can be used to provide high value services to a viewer.

In the preferred embodiment, the first step in providing audio iscollecting the audio. This is done through the use of standard audiocapture. Next, the audio must be distributed. This is preferably doneeither in-band via broadcast or out-of-band through some other transportchannel. In-band audio is preferably provided via an MPEG streamassociated with the current television program. However, delivery of theaudio via other broadcast mechanisms has the same effect. Within abroadcast cable, satellite or terrestrial system, all audio related to agiven video program are generally included in the same RF channel.Out-of-band (OOB) audio can be transmitted as well, although it ispreferable to select which channel is distributed upstream. That is,only the desired audio channel(s) are sent over the OOB channel, e.g.after viewer selection from a plurality of choices. With either system,the set top box is used by the viewer to select the appropriate audiochannel(s) and to route the television audio to a television or to aseparate amplifier and speakers for reproduction.

The audio is preferably tagged with metadata, such that informationdescribing the audio accompanies each audio channel. There are variousways of delivering tag data and associating it with the audio, such asdelivering the data along with other information that identifies theprogram, delivering separate data in conjunction with the audio, orembedding the data with the audio as part of the audio encoding, Suchtagging allows, for example, a description of the audio to be providedto the viewer as part of a selection mechanism (see below), and/orprovides control information that is used by the system, for example toconfigure the system for a particular type of audio processing, e.g.DTS; display accompanying graphic information; such as an ad; or engagea viewer authentication/billing mechanism, for example to provideupstream information concerning the viewer's selections. In addition,the metadata can be used to display a visual identification such as atext or graphics overlay to indicate to the viewer which selectableaudio track is presently selected. The visual identification could bedisplayed continuously or alternatively, could be displayed in responseto a user request initiated for example by a button on the remotecontrol.

The presently preferred embodiment of the invention provides twomechanisms for selecting audio, i.e. manual selection and assistedselection. With manual selection, the viewer is presented with variousoptions and determines which audio channel to use. For example, agraphics overlay can be presented on the television screen whichdisplays the available audio channels to the viewer. When a viewerpresses a selection key or moves a selection means, such as a cursor, toa particular item, the desired audio channel is selected. Assistedselection adds intelligence to the selection process. In this mode,information on the viewer's preference is either gathered directly fromthe viewer or via a separate mechanism, e.g. such preferences may beinferred from the viewer's viewing preferences or from a viewer profile.This information is used to prioritize or to cull the list of what isoffered, thereby only presenting the viewer with choices that are ofinterest to the viewer. For example, if the viewer is the fan of aparticular racer, that racer could always be offered first. Note thatprevious selections made by the viewer could be used as part of theinformation used to customize the list for the viewer.

The process of selecting audio can also include the application ofparental controls. For example, audio can be tagged with ratingsinformation, and parents can be provided the means, as is done withtraditional parental controls, to limit listening to approvedselections.

Additional audio programs can include closed captions. These captionscan be displayed on the television either with the audio or in lieu ofit. Note that this improves the monitoring of multiple audio programs.For example, a viewer may listen to one audio channel while he monitorsa closed caption version of another audio channel.

Additional audio selections may be offered as a premium that can bebilled through a variety of models, e.g. unlimited free, per use, andtotal time. The billing system for such premium selections is preferablyincorporated in a billing method that is similar to that ofvideo-on-demand (VOD). The basic elements of such billing system includeordering, provisioning, i.e. turning on the audio, and billing. Notethat for audio to be billed, it should include conditional access. Thiscan take advantage of existing conditional access systems, or it can behandled via web rights management methods, e.g. using SSL.

Viewers may wish to monitor multiple audio channels simultaneously. Thisis typically difficult to do because people are not very good atdiscriminating between multiple sources of audio in real time. However,the invention provides various options, such as mixing into single audiotrack; sending different audio tracks to different speakers in amulti-channel audio; displaying text information on the screen for audiothat includes text information, e.g. closed caption; and combinations ofthe above approaches.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block schematic diagram of a multi-channel audio enhancementfor television according to the invention;

FIG. 2 is a block schematic diagram showing audio capture for a NASCARrace according to the invention;

FIG. 3 is a block schematic diagram of a set top box according to theinvention;

FIG. 4 is a flow diagram showing a multiplexing and demultiplexingprocess according to the invention;

FIG. 5 is a flow diagram showing multi-channel audio enhancement fortelevision according to the invention; and

FIG. 6 is a diagram of a sample viewer interface according to theinvention.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a comprehensive mechanism for broadcasting andaccessing multiple audio sources in connection with the viewing of atelevision or other program.

For purposes of the discussion herein, the following terms have themeaning associated therewith:

DTS—A set of audio encoding techniques (licensed through DTS Technology,Inc.) not to be confused with MPEG Decoding Time Stamp.

MPEG—Motion Picture Experts Group, a set of standards for audio andvideo coding. Many of these are international standards.

System Information—when used in context, refers to information about TVprograms including information.

In the preferred embodiment, the first step in providing audio iscollecting the audio. This is done through the use of standard audiocapture. Collected audio is delivered from the location where it iscaptured, for example, a racetrack, to the point where it will bedelivered to a viewer, for example, a headend, a satellite groundstation or a terrestrial broadcast studio. Once the audio is at thispoint, the audio must be distributed. This is preferably done eitherin-band via broadcast or out-of-band through some other transportchannel.

The audio is preferably tagged with metadata, such that informationdescribing the audio accompanies each audio channel. This allows, forexample, a description of the audio to be provided to the viewer as partof a selection mechanism (see below), and/or provides controlinformation that is used by the system, for example to configure thesystem for a particular type of audio processing, e.g. DTS; displayaccompanying graphic information; such as an ad; or engage a viewerauthentication/billing mechanism, for example to provide upstreaminformation concerning the viewer's selections. The tagging may occur inmany ways. In a preferred embodiment, information is added to the SystemInformation (SI) data that is part of an MPEG program. In anotherembodiment, the data can be encoded with the audio itself such that thetag data is delivered in an MPEG elementary stream. In anotherembodiment data may be sent independently of the audio and videostreams, possibly prior to the program being broadcast. Those skilled inthe art will appreciate that information may be added to the audio inother ways in connection with the invention.

In-band audio is preferably provided via an MPEG stream associated withthe current television program. However, delivery of the audio via otherbroadcast mechanisms has the same effect. Within a cable system, audiois included in the same channel.

Out-of-band (OOB) audio can be broadcast as well, although it ispreferable to select which channel is distributed upstream. That is,only the desired audio channel(s) are sent over the OOB channel, e.g.after viewer selection from a plurality of choices.

With either system, the set top box is used by the viewer to select theappropriate audio channel(s) and to route the television audio to atelevision or to a separate amplifier and speakers for reproduction.

The presently preferred embodiment of the invention provides twomechanisms for selecting audio, i.e. manual selection and assistedselection.

With manual selection, the viewer is presented with various options anddetermines which audio channel to use. For example, a graphics overlaycan be presented on the television screen which displays the availableaudio channels to the viewer. When a viewer presses a selection key ormoves a selection means, such as a cursor, to a particular item, thedesired audio channel is selected.

Assisted selection adds intelligence to the selection process. In thismode, information on the viewer's preference is either gathered directlyfrom the viewer or via a separate mechanism, e.g. such preferences maybe inferred from the viewer's viewing preferences or from a viewerprofile. This information is used to prioritize or to cull the list ofwhat is offered, thereby only presenting the viewer with choices thatare of interest to the viewer. For example, if the viewer is the fan ofa particular racer, that racer could always be offered first. Note thatprevious selections made by the viewer could be used as part of theinformation used to customize the list for the viewer.

The process of selecting audio can also include the application ofparental controls. For example, audio can be tagged with ratingsinformation, and parents can be provided the means, as is done withtraditional parental controls, to limit listening to approvedselections.

Additional audio programs can include closed captions. These captionscan be displayed on the television either with the audio or in lieu ofit. Note that this improves the monitoring of multiple audio programs.For example, a viewer may listen to one audio channel while he monitorsa closed caption version of another audio channel.

Additional audio selections may be offered as a premium that can bebilled through a variety of models, e.g. unlimited free, per use, andtotal time. The billing system for such premium selections is preferablyincorporated in a billing method that is similar to that ofvideo-on-demand (VOD). The basic elements of such billing system includeordering, provisioning, i.e. turning on the audio, and billing. Notethat for audio to be billed, it should include conditional access. Thiscan take advantage of existing conditional access systems, or it can behandled via web rights management methods, e.g. using SSL.

Viewers may wish to monitor multiple audio channels simultaneously. Thisis typically difficult to do because people are not very good atdiscriminating between multiple sources of audio in real time. However,the invention provides various options, such as mixing into single audiotrack; sending different audio tracks to different speakers in amulti-channel audio; displaying text information on the screen for audiothat includes text information, e.g. closed caption; and combinations ofthe above approaches.

Discussion of a Presently Preferred Embodiment of the Invention

FIG. 1 is a block schematic diagram of a multi-channel audio enhancementfor television according to the invention. In this embodiment, aplurality of radios or other capture mechanisms 10, e.g. microphones,are used to capture the audio of interest. A resulting analog and/ordigital signal or signals 11 is provided to an audio capture module 12,which digitizes (if necessary) and buffers the audio. The audio is thenprocessed to provided and MPEG stream 16. MPEG processing is well knownin the art and is not discussed at greater length herein. Those skilledin the art will appreciate that other processing schemes may be used inconnection with the invention. Further, it will be appreciated thatanalog schemes, such a frequency division multiplexing (FDM) may be usedin connection with, or instead of, digital schemes.

The MPEG stream is presented to a multiplexor 14, which also receivesvideo and audio production information via an MPEG stream 13 from avideo and audio production module 19; and that receives metadata as anMPEG stream 17 from a metadata generator 18. Those skilled in the artwill appreciate that such processing and multiplexing may employmechanisms other the MPEG and may comprise data in the analog domain, aswell as or alternatively to, the digital domain.

The multiplexor produces a composite MPEG stream 15 that comprises thevideo program material, metadata, and the multiple audio channels. Otherembodiments of the invention may provide the metadata and or audioseparately from the video program material.

A standard transport mechanism 23, such as a cable television orsatellite television system, is used for the broadcast, transmission,and reception of the MPEG stream 15. This transport mechanism cancomprise a combination of ground stations, broadcast facilities,satellites, head ends, cable networks, and terrestrial broadcastfacilities, as are well known in the art. A resulting broadcast MPEGstream 25 is provided to a viewer location for decoding, for exampleusing a set top box 24.

FIG. 2 is a block schematic diagram showing audio capture for a NASCARrace according to the invention. In this example of the invention, arack of radios 10 is provided in which each radio corresponds to asingle channel of audio. The use of the term radio here refers to thefact that the system would monitor the personal communications channelsof each driver with his pit crew. In this sense, the term radio is usedgenerically to refer to any source of audio, and is not limited only toradio frequency broadcast information.

The plurality of radio signals 11 is routed from the rack of radios to amulti-channel digitization card 20 within a capture computer 22. Theaudio stream 16 is then provided to a multiplexor card 14, which alsoreceives an MPEG audio and video stream 13, e.g. over a network. In thisembodiment, the audio stream 16 is also provided to a disk or otherstorage mechanism 21 for buffering if the audio stream is not providedin real time and metadata 17 is generated and provided to themultiplexor card. An MPEG stream 15 is output that comprises combinedvideo, audio, enhancement audio, and metadata. In one embodiment of theinvention, it is preferred to add timing to the audio data to ensurethat timing is maintained all the way through playback.

FIG. 3 is a block schematic diagram of a set top box according to theinvention. The set top box 24 receives the MPEG stream via atransmission method 23 which, in this example, comprises a cable orantenna 30 and receiver 31 at the viewer's home.

The MPEG stream thus received is provided to an MPEG decoder 32 whichextracts the metadata 42, video 44, and enhanced audio 45 therefromunder control of a processor/memory 34. The video stream 44 is providedto a video mixer 36 in a multimedia chip 35. The processor controlswhich audio streams extracted from the MPEG stream are provided to anaudio mixer 37 in the multimedia chip via a control mechanism 41. Theprocessor also extracts metadata 42 from the MPEG stream via a controlmechanism 40 for application use, for example to derive graphics 43therefrom that describe the enhancement audio. The system then outputsboth audio 38 and video 39 for reproduction on the viewer's televisionand/or other viewer equipment (not shown). If timing information isincluded, then the audio is synchronized with the video. Because set topboxes are well known in the art, an additional description thereof isnot provided.

FIG. 4 is a flow diagram showing a multiplexing and demultiplexingprocess according to the invention. The preferred embodiment of theinvention multiplexes a standard audio/video signal/stream 13 with aplurality of enhancement audio stream 16 and metadata 17 using amultiplexing mechanism 14. The combined stream is broadcast and adecoding/extraction process 32 separates the various streams into video44, closed caption information 43 (if applicable), audio 45 (which isselected from among standard and enhancement audio), and metadata 42.

FIG. 5 is a flow diagram showing multi-channel audio enhancement fortelevision according to the invention. In this process, multiplechannels of audio are received (102) and digitized (104). Metadata isalso generated (100), and the metadata and digitized audio are taggedand multiplexed (106). The data are then transmitted (108), received atthe viewer's set top box (110), and the metadata is extracted anddisplayed to the viewer (112) for use in determining which audio channelto select. Responsive thereto, the set top box, typically underprocessor control, configures the system to select and process anappropriate audio stream (114).

As discussed above, it is preferred to conserve bandwidth. When the userhas a dedicated channel such as an OOB channel in a broadcast network, adedicated channel on a shared network such as done with video on demand(VOD), where a dedicated link, such as DSL, is used for audio and videodelivery the following technique can be used to conserver bandwidth.Note that this would not apply to a strictly broadcast facility becauseall users would hear the same audio and they could not effectivelyselect their own. The several channels of enhancement audio may beidentified via the metadata, but they are not all themselves transmittedto the set top box at the same time. Rather, viewer selection of one ormore specific channels results in an interactive, upstream transmissionto a head end or central location, thereby instructing the system whichparticular audio channels are to be transmitted. This up streamcommunication may also contain authorization and/or billing information.In addition to conserving bandwidth, this approach also minimizes theneed for a dedicated set top box. Rather, legacy systems may be readilyadapted to use the invention, for example, by stripping out standardaudio, closed caption and SAP information, and inserting user selectedinformation in place thereof

FIG. 6 is a diagram of a sample viewer interface according to theinvention. On a typical display 60, the viewer is presented with videoand/or graphics 62 during the enhancement audio selection process.Various other information 66, such as advertising, billing information,or program statistics, may also be provided. The viewer controls theselection process through a control mechanism 64, such as a cursormechanism or a simple numeric selection via the viewer's remote control.Thereafter, the viewer's selection may be confirmed and the viewerbegins to receive the selected enhancement audio. While a simple viewerinterface is shown in FIG. 6, it will be appreciated by those skilled inthe art that additional functions may be provided to the viewer, such asfor example, fader controls when multiple channels of audio are selectedfor simultaneous reception, authorization dialogs, parental controldialogs, and closed caption controls.

Data Structures

Tables 1-4 below show a simple metadata description for multi-channelaudio enhancement, in which Table 1 shows an audio enhancementstructure; Table 2 shows a data title structure; Table 3 shows anenhancement channel structure; and Table 4 shows a data value structure.

TABLE 1 Audio Enhancement Structure Field Data Type Description Shorttitle length Binary Length of following field Short title Text Briefdescription of audio enhancement Title length Binary Length of followingfield Title Text Longer description of audio enhancement Number of dataBinary Number of data descriptors description fields for each channelNumber of Binary Number of additional Enhancement audio channelsChannels Data Titles Data title structure One for each of “number datadescriptors” Enhancement Enhancement One for each of Channel Structureschannel structure “Number of Enhancement Channels”

TABLE 2 Data title structure Field Data Type Description Descriptortitle length Binary Length of followi

field Descriptor title Text Text descripto

Length = Descript

value length

indicates data missing or illegible when filed

TABLE 3 Enhancement channel structure Field Data Type Description DataValues Data Value Structure One for ea

“Number of da

descriptors” in Au

Enhancement Structure

indicates data missing or illegible when filed

TABLE 4 Data Value Structure Field Data Type Description Descriptorvalue length Binary Length of following

indicates data missing or illegible when filed

EXAMPLE

The following provides a pseudo-code example of an audio enhancementdata structure according to the invention. Note that // and everythingafter // is a comment.

-   //Audio Enhancement Data Structure-   12, “NASCAR Audio”, //short title length and title-   33, “NASCAR Audio for Jan. 17, 2002” II title length and title-   3//number of data descriptors-   24//number of enhancement channels-   //Data Title Structure-   6, “Driver”-   5, “Freq.”-   5, “Car #”-   //Enhancement channel structure consists of Data value structures-   //first Data value structure-   5, “Smith”-   6, “192.13”-   1, “7”-   //next Data value structure-   5, “Jones”-   6, “193.23”-   2, “22”-   //in this example, 22 more entries would follow-   . . .

The data above are added either to the data itself, thereby creating anew audio data type; or to the system information (SI) that comes withMPEG data, e.g. DVB-SI or PSIP. In the former case, the audio encoding,e.g. PCM 44.1 kHz 16-bit or AC-3, is also added. In the latter case, theSI information is enhanced to add this data type, but there are alreadyprovisions within most established SI data structures for describing theaudio format.

Although the invention is described herein with reference to thepreferred embodiment, one skilled in the art will readily appreciatethat other applications may be substituted for those set forth hereinwithout departing from the spirit and scope of the present invention.Accordingly, the invention should only be limited by the claims includedbelow.

1. (canceled)
 2. An apparatus comprising: one or more processors; andmemory storing instructions that, when executed by the one or moreprocessors, cause the apparatus to: receive a multiplexed signalcomprising a video signal, a plurality of audio signals, and metadatacomprising rating information for each of the plurality of audiosignals; receive a selection of an audio signal of the plurality ofaudio signals; and cause output of the video signal and the selectedaudio signal in response to a determination, based on the ratinginformation, that the selected audio signal corresponds to an approvedselection.
 3. The apparatus of claim 2, wherein the metadata furthercomprises a description of audio content of each of the plurality ofaudio signals.
 4. The apparatus of claim 3, wherein the description ofaudio content indicates that a first audio signal of the plurality ofaudio signals comprises audio commentary from a first source and that asecond audio signal of the plurality of audio signals comprises audiocommentary from a second source.
 5. The apparatus of claim 2, whereinthe audio signals comprise Motion Picture Experts Group (MPEG) encodedsignals.
 6. The apparatus of claim 2, wherein the instructions, whenexecuted by the one or more processors, further cause the apparatus to:determine preference information based on input information or onviewing preferences to assist a user in selecting the audio signal. 7.The apparatus of claim 6, wherein the preference information comprisesinformation for prioritizing an order of titles of two or more of theplurality of audio signals based on the preference information forsimultaneous presentation of the titles in the order.
 8. The apparatusof claim 6, wherein the instructions, when executed by the one or moreprocessors, further cause the apparatus to: prioritize an audio signallist comprising the plurality of audio signals based on the preferenceinformation; and cause presentation of the audio signal list.
 9. Theapparatus of claim 6, wherein the instructions, when executed by the oneor more processors, further cause the apparatus to: modify, based on thepreference information, an audio signal list comprising the plurality ofaudio signals to generate a modified audio signal list; and causepresentation of the modified audio signal list.
 10. An apparatuscomprising: one or more processors; and memory storing instructionsthat, when executed by the one or more processors, cause the apparatusto: receive content that comprises a video signal, a plurality of audiosignals, and metadata associated with the plurality of audio signals,wherein the metadata comprises rating information; determine, based onthe metadata, a subset of the plurality of audio signals; receive aselection of an audio signal of the subset of the plurality of audiosignals; and output the video signal and the selected audio signal. 11.The apparatus of claim 10, wherein the instructions, when executed bythe one or more processors, further cause the apparatus to: decode thecontent from a multiplexed signal.
 12. The apparatus of claim 10,wherein the metadata further comprises at least one of a description ofthe audio signal, information identifying the audio signal, and controlinformation for use in processing the audio signal.
 13. The apparatus ofclaim 12, wherein the description of the audio signal comprisesinformation for prioritizing an order of titles of two or more of theaudio signals based on viewer preferences for simultaneous presentationof the titles in the order.
 14. The apparatus of claim 10, wherein theaudio signals comprise MPEG encoded signals.
 15. The apparatus of claim10, wherein the instructions, when executed by the one or moreprocessors, further cause the apparatus to: determine preferenceinformation based on at least one of input information and viewingpreferences, wherein the subset of the plurality of audio signals isfurther determined based on the preference information.
 16. Theapparatus of claim 15, wherein the instructions, when executed by theone or more processors, further cause the apparatus to: modify, based onthe preference information, an audio signal list comprising theplurality of audio signals to generate a modified audio signal list; andcause presentation of the modified audio signal list.
 17. The apparatusof claim 10, wherein the instructions, when executed by the one or moreprocessors, further cause the apparatus to: cause presentation of thesubset of the plurality of audio signals.
 18. An apparatus comprising:one or more processors; and memory storing instructions that, whenexecuted by the one or more processors, cause the apparatus to: receivea video signal, a plurality of audio signals, and metadata, wherein eachof the plurality of audio signals is associated with correspondingmetadata; determine, based on a user preference and the metadata, asubset of the plurality of audio signals; cause output of a selectableaudio feature comprising the subset of the plurality of audio signals;receive a selection of an audio signal of the subset of the plurality ofaudio signals; and cause output of the video signal and the selectedaudio signal.
 19. The apparatus of claim 18, wherein the instructions,when executed by the one or more processors, further cause the apparatusto determine the user preference based on user input received from auser input device.
 20. The apparatus of claim 18, wherein the metadatacomprises rating information and wherein the subset of the plurality ofaudio signals is further determined based on the rating information. 21.A system, comprising: a first computing device configured to: generatecontent comprising a video signal, a plurality of audio signals, andmetadata associated with the plurality of audio signals, wherein themetadata comprises rating information; and cause output of the content;and a second computing device configured to: receive the content thatcomprises the video signal, the plurality of audio signals, and themetadata associated with the plurality of audio signals; determine,based on the metadata, a subset of the plurality of audio signals;receive a selection of an audio signal of the subset of the plurality ofaudio signals; and cause output of the video signal and the selectedaudio signal.
 22. The system of claim 21, wherein the metadata furthercomprises a description of audio content of each of the plurality ofaudio signals.
 23. The system of claim 22, wherein the description ofaudio content indicates that a first audio signal of the plurality ofaudio signals comprises audio commentary from a first source and that asecond audio signal of the plurality of audio signals comprises audiocommentary from a second source.
 24. The system of claim 21, wherein thesubset of the plurality of audio signals is further determined based onthe rating information.